Shaped explosive charge devices



Feb. 15, 1966 J. DELACOUR 3,235,005

SHAPED EXPLOSIVE CHARGE DEVICES Original Filed Oct. 8, 1956 2Sheets-Sheet 1 INVENTOR JACQUES DELACOU R HIS ATTORN EYS.

Feb. 15, 1966 J DELACOUR 3,235,005

SHAPED EXPLOSIVE CHARGE DEVICES Original Filed Oct. 8, 1956 2Sheets-Sheet 2 FIG. 7

FIG. 8

United States Patent 3,235,005 SHAPED .EXPLOSIVE CHARGE DEVICES JacquesDelacour, Paris, France, assignor to Societe de Prospection' Electrique,Procedes Schlumberger, Paris, France, a corporation of FranceContinuation of application Ser. No. 614,395, Oct. 8, 1956. Thisapplication Dec. 29, 1961, Ser. No. 164,430 Claims priority, applicationFrance,Nv. 9, 1955, 702,313 Claims. (Cl. 166-36) This invention relatesto shaped'explosive charges and more particularly to new and improvedshaped explosive charge devices which are capableof producing in hardmaterials greatly improved cracking .or breaking effects which incertain cases may occur after perforation has taken place.

This application is a continuation of application Serial No. 614,395,filed October 8, 1956.

In petroleum technology, shaped explosive charge devices are frequentlyemployed toperforate well casing and any surrounding body of'cement andformation material in order to bring a well'into production. While theperforating jets from such devices do penetrate the casing effectivelyand produce cracks in any surrounding cement, sometimes such cracking ofthe cement is only partially effective so that the throughput of fluidfrom any oil containing stratum behind the cement through the cracks andperforations is relatively small.

Shaped charge devices of this general character have also not been foundentirely satisfactory for breaking up large blocks of rock in quarriesor the like, since the number of fragments produced .is often verysmall.

It is an object of the invention, accordingly, to provide new andimproved shaped explosive charge devices of the above character whichare capable of producing increased cracking and breaking effects.

Another object of the invention is to provide new and improved shapedexplosive charge devices of the above character which, in well casingperforating operations, provide for the cleaning of the perforationswhich otherwise might be completely or partially plugged up with foreignmatter of one kind or another.

To this end, the invention consists in providing between the actualexplosive charge and the cavity which characterizes the shaped or hollowcharge a substance or a mixture of substances which is adapted toproduce a highly exothermic chemical reaction under the action of theexplosion. The chemical reaction may result from the interaction betweenthe ingredients of the substance or mixture of substances, or it mayinvolve said ingredients and the products of the explosion or even thecomponents of the target. While the eaction should be of a highlyexothermic character, it should not be explosive; in fact, it shouldhave a speed of propagation which is substantially lower than the speedof detonation of the explosive forming the actual charge.

In practice, this result may be obtained by coating the usual chargeliner, whether of metal or otherwise, which generally separates theexplosive from the free space in the cavity of the charge with a layerof such a substance or mixture of substances. This layer may be disposedeither over the whole surface of the liner, or only on :part of thesurface in the shape of a ring or separated elements, for example.

The active substance may furthermore be arranged either on the frontsurface of the liner or on the rear surface thereof facing theexplosive, or again on both surfaces. Alternatively, thecharge liner maybe made out of a substance or mixture of substances having theproperties defined hereinabove.

3,235,005 Patented Feb. 15, 1966 It has been found that shaped explosivecharge devices constructed according to the invention have a much higherbreaking action than that of conventional hollow charges. This actionaffects the material which has been previously perforated by the chargeby reason of the fact that the exothermic reaction progresses onlyinside the mass of material which is tobe cracked. Such cracking andbreaking effects are not obtained when conventional shaped chargedevices are used.

As mentioned hereinabove, the invention is applicable in particular toshaped explosive charge devices which serve for perforating the casinglining the side wall of a Well together with any cement lying behindsaid casing, said devices being used at the level of the oil carryingstrata for the purpose of bringing the well into production. Withconventional shaped charges, the perforating jet generally perforatesthe casing and the sur rounding cement fairly effectively but the cracksobtained in the cement are generally insufficient and consequently thefluid lying inside the oil containing strata behind the cement can flowthrough the cracks and perforations only with a very small throughput.

With shaped charges according to the invention, it is possible toproduce in the cement masses and in the adjacent strata of the ground,large cracks which remain open as mentioned hereinabove and throughwhich the fluid may flow out until it reaches the perforations in thecasing. This obviously increases to a considerable extent the throughputof fluid passing out of said perforations.

In the case of block breaking charges, these improved shaped chargesenable large blocks to be broken into a great number of fragments,whereas the conventional shaped charges produce a very small number offrag ments.

Among the substances or mixtures of substances which may be used toproduce the desired reactions, may be mentioned more particularlytitanium alone, or any other metal forming part of the titanium group,such as zirconium, hafnium, thorium, .etc., or a mixture or alloy ofsuch metals.

Any of the following mixtures may also be used.

Various embodiments of the invention have been shown diagrammatically onthe accompanying drawings.

FIG. 1 is a view in longitudinal section of a shaped charge according toa first embodiment of the invention.

FIGS. 2, 3, 4, 5 and 6, are similar views of other embodiments of shapedexplosive charge devices according to the invention;

FIG. 7 is a View in longitudinal section of a casing perforating devicein which any of the charges shown in FIGS. l-6, inclusive, may beemployed; and

FIG. 8 is a view in longitudinal section of another embodiment of theinvention.

In FIG. 1, 1 denotes the casing of a shaped explosive charge device inwhich is formed a chamber containing an explosive charge 2 which isadapted to be detonated by a detonating device of any suitable type 3set, for instance, at the rear of the charge. Formed in the explosivecharge 2 in a conical cavity 4 provided with a liner 5, which, accordingto the invention, is made of titaniurn, for instance, or of any othersubstance capable of creating a highly exothermic reaction upondetonation of the charge.

In the embodiment of FIG. 2, the conical liner 5 is made of copper or ofany other neutral substance, but

this liner has a coating 6 on its outer surface of a substance capableof creating an exothermic reaction of the type hereinabove indicated,the thickness of said coating (titanium, for instance) beingapproximately 1 mm.

The charge shown in FIG. 3 differs from that shown in FIG. 2 only inthat the coating 6' intended to create the exothermic reaction isdisposed behind the liner 5.

The device shown in FIG. 4 is the same as that of FIG. 2, but with thedifference that the coating 7 is not laid down over the whole surf-aceof the liner 5 but is in the form of a truncated cone ring.

In FIG. 5, a corresponding ring 7 is set behind the liner 5.

Lastly, in FIG. 6, the ring of FIG. 4 is replaced by discrete portions13 evenly distributed over the surface of the liner.

All of the shaped charge devices shown in the figures described abovecan be used either directly as block breakers or for perforating thecasing lining the inner wall of an oil well.

FIG. 7 shows a charge of one of the hereinabove types shown in FIGS. l6,inclusive, embodied in casing perforating apparatus.

In FIG. 7, 8 denotes a cylindrical hollow extended body which is adaptedto house a stack of longitudinally spaced apart shaped explosive chargedevices (only one of which is shown in the figure) for perforating theeasing 9 lining the inner wall of an oil well, together with any body ofcement lying between the casing and the well wall. 1 denotes the shapedcharge case; 3 a detonating device comprising a length of primacordwhich is in detonating relation to all the charges in the apparatus; 2the explosive charge; and 5 the liner set in the for-ward cavity of thecharge. The whole shaped charge assembly is introduced laterally throughan opening in the forward wall of the cylinder 8 and is retained inplace by a plug 10 screwed in the said opening, the case 1 bearing onthe front edge of the opening on the one hand, and in the recess 11formed in the rear wall of the cylinder 8 on the other hand. The plug 10is intended to be perforated in its center by the jet.

According to the invention, the liner 5 is made either of a materialcreating an exothermic reaction or of a neutral material coated entirelyor partly with a substance having these properties, as in FIGS. 1-6,inclusive.

Experiments have shown that the use of such a shaped charge in thisparticular case not only enables a better splitting of the cement and ofthe geologic strata lying behind the tubing 9 to be obtained, but alsoacts to clean out the perforations which otherwise might fill up withforeign matter of one kind or another. By keeping the perforations cleanand free of foreign matter in this manner, the throughput of the fluidfrom the formations is, of course, increased.

The embodiment of FIG. 8 comprises a device having one of the shapedexplosive charges shown in FIGS. l6, inclusive, assembled in a wellknown manner into a housing 1 provided with a tightly-fitting stopper12. In this embodiment, the assembly constitutes a complete unit whichis pressure-resistant and capable of being freely lowered down a borehole without being placed inside a housing, such as the housing 8 inFIG. 7. If desired, a plurality of devices as in FIG. 8 may be suspendedin a well-known manner one above the other inside the bore hole. Also,devices of this type can, without modification, be used as blockbreakers.

It is obvious that the specific embodiments described above aresusceptible of modification in form and detail within the spirit of theinvention. Therefore, the latter is not to be limited to the exemplarydevices herein disclosed, but comprehends all variations thereof fallingwithin the scope of the following claims.

I claim:

1. A shaped explosive charge device for perforating formation materialsand cracking such materials or cleaning the resulting perforationcomprising an explosive charge having a hollow cavity formed in thefront part thereof, a liner for the entirety of said cavity disposed incontact with said explosive charge, said liner having a substantiallyuniform wall thickness and being composed substantially entirely of areactive metal and cooperating with said explosive charge for forming aperforating jet which can penetrate said formation materials, saidreactive metal being capable of producing a highly exothermic reactionin the penetrated formation materials and capable of exerting crackingforces therein, the reaction of said reactive metal having a rate ofpropagation which is lower than the rate of detonation of said explosivecharge, said cavity being otherwise free of any mass.

2. A shaped explosive charge device for perforating earth formations andcracking such earth formations adjacent a well bore or cleaning theresulting perforation comprising an explosive charge having a hollowcavity formed in the front part thereof, a liner for the entirety ofsaid cavity disposed in contact with said explosive charge, said linerbeing composed substantially entirely of a reactive metal andcooperating with said explosive charge for forming a perforating jetwhich can penetrate said formations, said reactive metal being capableof producing a highly exothermic reaction in the penetrated formationand capable of exerting cracking forces therein, the reaction of saidreactive metal having a rate of propagation wihch is slower than therate of detonation of said explosive charge, said cavity being otherwisefree of any mass.

3. A shaped explosive charge device for perforating formation materialsand cracking such materials or cleaning the resulting perforationcomprising an explosive charge having a generally hollow cavity formedin the front part thereof, a liner for said entire cavity in contactwith said explosive charge and capable of collapsing upon detonation ofsaid charge to form a fluid jet, said liner being composed substantiallyentirely of a metal of the group consisting of titanium, zirconium,hafnium, thorium and mixtures thereof and being capable of producing, ahighly exothermic reaction in the penetrated formation materials andcapable of exerting cracking forces therein, the reaction of said metalliner having a rate of propagation which is slower than the rate ofdetonation of said explosive charge, said cavity being otherwise free ofany mass.

4. A shaped explosive charge device for perforating formation materialsand cracking such materials or cleaning the resulting perforationcomprising an explosive charge having a generally hollow cavity formedin the front part thereof, a liner for said entire cavity in contactwith said explosive charge and capable of collapsing upon detonation ofsaid charge to form a fluid jet, said liner being composed substantiallyentirely of titanium and being capable of producing, a highly exothermicreaction in the penetrated formation materials and capable of exertingcracking forces therein, the reaction of said reactive liner having arate of propagation which is slower than the rate of detonation of saidexplosive charge, said cavity being otherwise free of any mass.

5. A shaped explosive charge device for perforating formation materialsand cracking such materials or cleaning the resulting formationcomprising an explosive charge having a generally hollow cavity formedin the front part thereof, a liner for said entire cavity in contactwith said explosive charge and capable of collapsing upon detonation ofsaid charge to form a fluid jet, said liner being composed substantiallyentirely of thorium and being capable of producing, a highly exothermicreaction in the penetrated formation materials and capable of exertingcracking forces therein, the reaction having a rate of propagation whichis slower than the rate of detonation of said explosive charge, saidcavity being otherwise free of any mass.

6. A shaped explosive charge device for perforating formation materialsand cracking such materials or cleaning the resulting perforationcomprising an explosive charge having a generally conical cavity formedin the front part thereof, a liner for said entire cavity in contactwith said explosive charge and capable of collapsing upon detonation ofsaid charge to form a fluid jet, said liner being composed substantiallyentirely of titanium nand being capable of producing, when ignited, ahighly exothermic reaction having a rate of propagation which is slowerthan the rate of detonation of said explosive charge to exert crackingforces in said mass of material when the mass of material is penetrated,said cavity being otherwise free of any mass.

7. The method of penetrating earth formations surrounding a well bore bymeans of a shaped explosive charge including the steps of providing aliner for said charge comprised at least in substantial part of areactive metal capable of producing when activated, a highly exothermicreaction, detonating said charge to produce a perforation in saidformation and carry the reactive metal of said liner into theperforation for activation therein, activating said reactive metal insaid perforation to create pressure forces in the formation massessurrounding the perforation effective to crack the masses and maintainthe perforation substantially free of debris.

8. The method of penetrating earth formations surrounding a Well bore bymeans of a shaped explosive charge including the step-s of providing aliner for said charge comprised at least in substantial part of areactive metal of the group consisting of titanium, zirconium, hafnium,thorium and mixtures thereof, capable of producing when activated, ahighly exothermic reaction, detonating said charge to produce aperforation in said formation and carry the reactive metal of said linerinto the perforation for activation therein, activating said reactivemetal in said perforation to create pressure forces in the formationmasses surrounding the perforation effective to crack the masses andmaintain the perforation substantially free of debris.

9. The method of penetrating earth formations surrounding a well bore bymeans of a shaped explosive charge including the steps of providing aliner for said charge comprised at least in substantial part of titaniumcapable of producing when activated, a highly exothermic reaction,detonating said charge to produce a perforation in said formation andcarry the titanium of said liner into the perforation for activationtherein, activating said titanium in said perforation to create pressureforces in the formation masses surrounding the perforation effective tocrack the masses and maintain the perforation substantially free ofdebris.

10. The method of penetrating earth formations surrounding a Well boreby means of a shaped explosive charge including the steps of providing aliner for said charge comprised at least in substantial part of thoriumcapable of producing when activated, a highly exothermic reaction,detonating said charge to produce a perforation in said formation andcarry the thorium of said liner into the perforation for activationtherein, activating said thorium in said perforation to create pressureforces in the formation masses surrounding the perforation effective tocrack the masses and maintain the perforation substantially free ofdebris.

References Cited by the Examiner UNITED STATES PATENTS 2,323,303 7/1943Bluehdorn et a1. 10290 2,605,703 8/1952 Lawson.

2,650,539 9/1953 Greene 10221.6 2,972,948 2/1961 Dray 102-56 FOREIGNPATENTS 573,078 11/ 1945 Great Britain. 693,163 6/1953 Great Britain.

SAMUEL FEINBERG, Primary Examiner.

SAMUEL BOYD, Examiner.

1. A SHAPED EXPLOSIVE CHARGE DEVICE FOR PERFORATING FORMATION MATERIALSAND CRACKING SUCH MATERIALS OR CLEANING THE RESULTING PERFORATIONCOMPRISING AN EXPLOSIVE CHARGE HAVING A HOLLOW CAVITY FORMED IN THEFRONT PART THEREOF, A LINER FOR THE ENTIRELY OF SAID CAVITY DISPOSED INCONTACT WITH SAID EXPLOSIVE CHARGE, SAID LINER HAVING A SUBSTANTIALLYUNIFORM THICKNESS AND BEING COMPOSED SUBSTANTIALLY ENTIRELY OF AREACTIVE METAL AND COOPERATING WITH SAID EXPLOSIVE CHARGE FOR FORMING APERFORATING JET WHICH CAN PENETRATE SAID PRODUCING MATERIALS, SAIDREACTIVE METAL BEING CAPABLE OF PRODUCING A HIGHLY EXOTHERMIC REACTIONIN THE PENETRATED FORMATION MATERIALS AND CAPABLE OF EXERTING CRACKINGFORCES THEREIN, THE REACTION OF SAID REACTIVE METAL HAVING A RATE OFPROPAGATION WHICH IS LOWER THAN THE RATE OF DETONATION OF SAID EXPLO- 7.THE METHOD OF PENETRATING EARTH FORMATIONS SURROUNDING A WELL BORE BYMEANS OF A SHAPED EXPLOSIVE CHARGE INCLUDING THE STEPS OF PROVIDING ALINER FOR SAID CHARGE COMPRISED AT LEAST IN SUBSTANTIAL PART OF AREACTIVE METAL CAPABLE OF PRODUCING WHEN ACTIVATED, A HIGHLY EXOTHERMICREACTION, DETONATION SAID CHARGE TO PRODUCE A PERFORATION IN SAIDFORMATION AND CARRY THE REACTIVE METAL OF SAID LINER INTO THEPERFORATION FOR ACTIVATION THEREIN, ACTIVATING SAID REACTIVE METAL INSAID PERFORATION TO CREATE PRESSURE FORCES IN THE FORMATION MASSESSURROUNDING THE PERFORATION EFFECTIVE TO CRACK THE MASSES AND MAINTAINTHE PERFORATION SUBSTANTIALLY FREE OF DEBRIS.